1. Field of the Invention
The invention relates to a device for operating machine elements subject to wear-related play, especially for brakes of rail vehicles.
2. Description of the Related Art
The machine elements subject to wear-related play according to the present invention are, for example, couplings or brakes. Such machine elements are used to transmit driving and braking forces in rail vehicles. To interrupt and close the power flow, linings that withstand high thermal stresses and that permit an advantageous power flow curve are used. These linings are subject to wear, which results in gradually increasing wear-related play. To compensate for this wear-related play, readjustment devices are known.
For example, EP 0 174 690 discloses a prior art readjustment device of the adjustment nut and screw type that compensates for wear-related play in brakes by rotating the adjustment nut on a piston screw to alter the position of the piston screw. This readjustment device includes a control sleeve that, under spring force and via a first coupling, prevents rotary movement of the adjustment nut, thereby preventing a longitudinal readjustment movement of the piston screw. After the brakes experience a predetermined amount of wear, a piston rod for activating the brakes moves beyond a certain distance, releasing the first coupling and allowing adjustment of the play distance in keeping with the wear that has occurred on the linings. Further forward movement by the piston rod results in the connection of a second coupling, so that further movement of the adjustment nut on the screw is stopped. This mechanism for connecting and disconnecting the adjustment nut is complicated to construct and assemble and therefore, is expensive to manufacture.
According to, for example, reference DE OS 22 01 082, another prior art readjustment device for rail vehicle brakes is used in connection with a piston-cylinder arrangement for brake activation and a brake gear for brake power transmission. This reference also indicates that the known operating devices comprise several individual components that must be connected, so that their assembly is expensive. Furthermore, the known operating devices are self-sufficient systems and therefore cannot be monitored by an overall operating system, such, for example, as a braking system for monitoring and operating all brakes on a rail vehicle, with respect to operating state and wear and cannot be controlled by such a system in a differentiated manner. Thus, the known operating devices do not meet the prerequisites for active integration into an overall braking system